Add requestConnectionPriority support (#221)

* feat: add requestConnectionPriority

- Add BleConnectionPriority enum (balanced, highPerformance, lowPower)
- Add BleCapabilities.supportsConnectionPriorityApi flag
- Implement on Android via BluetoothGatt.requestConnectionPriority()
- Throw notSupported on iOS, macOS, Windows, Linux, and Web
- Update pigeon definition and regenerate platform channel files
- Bump version 1.2.0 -> 1.3.0

* fix: improve requestConnectionPriority implementation

- Remove redundant BleCapabilities guard in Dart layer (native handles it)
- Add BleConnectionPriority Kotlin enum mirroring Dart enum
- Map to explicit Android SDK constants via when expression
- Add firstOrNull with ILLEGAL_ARGUMENT for unknown priority values
- Add catch (e: Exception) block for broader error handling
- Fix enum doc comment (throws belongs on method, not enum)
- Remove stale capability check guidance from docs and README

---------

Co-authored-by: aqeel-bmec-co <aqeel@bmec.co>
Co-authored-by: aqeel-bmec-co <85945830+aqeel-bmec-co@users.noreply.github.com>

windows/src/generated/universal_ble.g.cpp

@@ -1389,6 +1389,41 @@ void UniversalBlePlatformChannel::SetUp(
       channel.SetMessageHandler(nullptr);
     }
   }
+  {
+    BasicMessageChannel<> channel(binary_messenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.requestConnectionPriority" + prepended_suffix, &GetCodec());
+    if (api != nullptr) {
+      channel.SetMessageHandler([api](const EncodableValue& message, const flutter::MessageReply<EncodableValue>& reply) {
+        try {
+          const auto& args = std::get<EncodableList>(message);
+          const auto& encodable_device_id_arg = args.at(0);
+          if (encodable_device_id_arg.IsNull()) {
+            reply(WrapError("device_id_arg unexpectedly null."));
+            return;
+          }
+          const auto& device_id_arg = std::get<std::string>(encodable_device_id_arg);
+          const auto& encodable_priority_arg = args.at(1);
+          if (encodable_priority_arg.IsNull()) {
+            reply(WrapError("priority_arg unexpectedly null."));
+            return;
+          }
+          const int64_t priority_arg = encodable_priority_arg.LongValue();
+          api->RequestConnectionPriority(device_id_arg, priority_arg, [reply](std::optional<FlutterError>&& output) {
+            if (output.has_value()) {
+              reply(WrapError(output.value()));
+              return;
+            }
+            EncodableList wrapped;
+            wrapped.push_back(EncodableValue());
+            reply(EncodableValue(std::move(wrapped)));
+          });
+        } catch (const std::exception& exception) {
+          reply(WrapError(exception.what()));
+        }
+      });
+    } else {
+      channel.SetMessageHandler(nullptr);
+    }
+  }
   {
     BasicMessageChannel<> channel(binary_messenger, "dev.flutter.pigeon.universal_ble.UniversalBlePlatformChannel.setLogLevel" + prepended_suffix, &GetCodec());
     if (api != nullptr) {

windows/src/generated/universal_ble.g.h

@@ -528,6 +528,10 @@ class UniversalBlePlatformChannel {
   virtual void ReadRssi(
     const std::string& device_id,
     std::function<void(ErrorOr<int64_t> reply)> result) = 0;
+  virtual void RequestConnectionPriority(
+    const std::string& device_id,
+    int64_t priority,
+    std::function<void(std::optional<FlutterError> reply)> result) = 0;
   virtual std::optional<FlutterError> SetLogLevel(const UniversalBleLogLevel& log_level) = 0;
 
   // The codec used by UniversalBlePlatformChannel.

windows/src/universal_ble_plugin.cpp

@@ -436,6 +436,14 @@ void UniversalBlePlugin::RequestMtu(
   }
 }
 
+void UniversalBlePlugin::RequestConnectionPriority(
+    const std::string &device_id, int64_t priority,
+    std::function<void(std::optional<FlutterError> reply)> result) {
+  result(create_flutter_error(
+      UniversalBleErrorCode::kNotSupported,
+      "requestConnectionPriority is not supported on Windows platform"));
+}
+
 void UniversalBlePlugin::ReadRssi(
     const std::string &device_id,
     std::function<void(ErrorOr<int64_t> reply)> result) {

windows/src/universal_ble_plugin.h

@@ -207,6 +207,9 @@ private:
       std::function<void(std::optional<FlutterError> reply)> result) override;
   void RequestMtu(const std::string &device_id, int64_t expected_mtu,
                   std::function<void(ErrorOr<int64_t> reply)> result) override;
+  void RequestConnectionPriority(
+      const std::string &device_id, int64_t priority,
+      std::function<void(std::optional<FlutterError> reply)> result) override;
   void ReadRssi(const std::string &device_id,
                 std::function<void(ErrorOr<int64_t> reply)> result) override;
   void IsPaired(const std::string &device_id,